Information technology (IT) administrators typically manage their organization's computer systems and associated components, such as telecommunications and storage systems in a facility commonly referred to as a datacenter. A large organization may include a wide range of hardware components (server machines, storage devices, communication equipment, and so on) and software components (firmware, operating systems, applications, and so on). Indeed, a large datacenter may be distributed over a wide geographic area in different parts of a city, in different states, or globally in different parts around the world. The term “datacenter” will be used herein to refer to the hardware and software components that constitute the computing, data storage, and communication infrastructure of an organization irrespective of whether the components are housed in a single building or distributed among different locations around the world.
Interrelationships between various parts of the datacenter may cause huge headaches for an IT department. In addition to managing large numbers of machines (servers, storage, and so on), differences between hardware, firmware, and software versions may easily create a combinatorial nightmare maintaining interoperability between hosts, databases, management appliances and other major software components. The combination of different hardware versions and software/firmware versions makes upgrading software in the datacenter a difficult process. If any one component does not upgrade successfully or becomes incompatible with other components as a result of the upgrade, entire portions of a datacenter may be rendered inoperable.
Further exacerbating the problem is the increasing deployment of virtualized environments within a datacenter. The term “virtualization” broadly describes the separation of a resource or request for a service from the underlying physical delivery of that service. Virtualization employs a software layer (virtualization layer) that decouples the physical hardware from the operating system. Virtualization allows multiple “virtual machines”, with heterogeneous operating systems and applications to run in isolation, side-by-side on the same physical machine. A virtual machine is the representation of a physical machine by software. It has its own set of virtual hardware (e.g., RAM, CPU, NIC, hard disks, etc.) upon which an operating system and applications are loaded. The operating system sees a consistent, normalized set of hardware regardless of the actual physical hardware components.
FIG. 6 shows a computer system having standard hardware components such as CPU, main memory, network interface card (NIC), and disk storage. A software layer called the virtualization layer has direct access to the underlying hardware and presents a hardware interface that appears to be a machine (virtual machine) on which an operating system (OS) may be installed along with subsequent applications. With virtualization, managing software becomes more complicated because a single hardware platform no longer may be assumed to support only one OS with one set of drivers, but rather may have multiple instantiations of different OS's with different sets of drivers. In fact, multiple instances of the same OS may each have different versions of the same driver.
More recently, virtualization has progressed to encompass systems of computers that include multiple hardware platforms. FIG. 7, for example, shows an underlying layer of physical components including, for example, physical servers 702, storage systems 704, and network 706. Each physical server 702 may be configured with a virtual layer 712 to manage the components as a pool of resources that may be allocated as virtual machines 714. Each virtual machine may then be installed with any one of a number of OS's. The ESX Server is an example of a virtualization layer 712. The ESX Server software package may be installed on each physical servers 702 to abstract processor, memory, storage, and networking resources to be provisioned to multiple virtual machines 714. A number of similarly configured physical servers 702 may be grouped together with connections to the same network 706 and storage systems 704 to provide an aggregate set of resources in a virtual environment. A management server 716 may provide services such as access control, performance monitoring and configuration. The management server 716 may unify resources from the individual physical servers 702 to be shared among virtual machines in the virtual environment.
As datacenters become increasingly more modular, multi-tiered, distributed, and virtualized, the datacenter infrastructure becomes more complex and managing all the interrelated software components that make up the infrastructure becomes increasingly challenging. Dependencies between related components and the compatibility limitations between those components makes for a daunting task when IT administrators must patch or upgrade any components within the system.